swihart



No. 6l2,069. Patented Oct. n, I898.

J. H. SWIHART.

SPRING BALANCE SCALE.

(Application filed Mar. 2, 1897.)

(No Model.)

3 Sheets-Shee t l.

Mfg-"Z11;

No. s|2,os9. Patented not. lI,-l898.

J. HrSWIHA'RT.

SPRING BALANCE SCALE.

(Application filed Mar. 2, 1897.) (No Ipdol.)

3 Sheets-Sheet 2.

m: NoRms wnzns co, movoumo. WASHINGTON. u, c.

' No. 6|2,069. Patented (let. u, I898.

, J. H. SWIHART.

SPRING BALANCE SCALE.

. (Application filed m. 2, 1897.) (No Model.) 3 SheetsSheet 3.

gfgfe tm e m UNITED STATES PATET @rrrcn.

JOHN HENRY SVVIHART, OF CLEVELAND, OHIO, ASSIGNOR TO THE NATIONALCOMPUTING SCALE COMPANY, OF SAME PLACE.

SPRING-BALANCE SCALE.

SPECIFICATION forming part of Letters Patent No. 612,069, dated October1 1, 1898.

, Application filed March 1397- To aZZ whom it may concern:

Be it known that I, JOHN HENRY SWIHART,

a citizen of the United States,residing at Cleveland, in the county ofOuyahoga and State of 5 Ohio, have invented certain new and usefulImprovements in Spring-Balance Scales; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention relates to improvements in spring-balance scales wherein ashaft to which an indicator (dial or pointer) is rigidly secured isproportionately rotated by the load upon the scale-pan.

The primary object of the invention is to prevent injury to the scaleand particularly to the dial or other form of indicator and itsconnection with the shaft when a weight is suddenly thrown upon or takenfrom the scale-pan.

The invention consists, broadly, in the combination of a rotatableshaft, an indicator rigidly secured thereto, and mechanism for operatingthe shaft with a spring-supported frame and a doubleactingspring-buffer, which is always under tension,which connects said framewith the shaft-operating mechanism and permits their relative movement,but compels them to come to rest in the same relation to each other. Italso consists in the combination of parts substantially as describedconstituting the double-acting springbuffer shown, in the combination,substantially as described,with the spring-supported frame, of adouble-acting spring-buffer adj ustably connected therewith,and in theother combinations of parts, as pointed out in the claims.

In the drawings, Figure 1 is a front View of the scale mechanism whenthe face-plate and dial have been removed. Fig. 2 is an enlarged View ofthe spring-supported frame and the mechanism which transmits motion fromit to the shaft to which the dial is secured, a part of said mechanismbeing shown in vertical section. Fig. 3 is a vertical sectional view ofthe scale near the axis of the shaft. Fig. 4 is a transverse verticalsectional view on line f 4 of Fig. 2. Fig. 5 is a View of amodifiedconstruction. Fig. 6 is a Serial No. 625,714. (No model.)

sectional view on lined 6 of Fig. 5, looking upward; and Fig. 7 is asectional view of another modified construction.

Referring to the parts by letters, A represents the scale-case;B,ahorizontaltransverse shaft which is supported in journals which maybe formed in the front and back plates a a of the case and in a fixedarm o The indicator G, as shown, is a dial, a part of which may be seenin Fig. 3. Its frame 0 is rigidly connected with the shaft by means of aplate b,which is rigidly fixed to said shaft. The frame D, which in itsgeneral form is like similar frames heretofore used, is suspended in theusual manner from the two scale-springs H H and projects out through thebottom of the case. The scale-pan, which is not shown, is to besuspended from the loop (I on the lower end of this frame. The frame D,as shown, is formed of two bars d d, the lower portions of which areparallel and are rigidly connected at a suitable distance apart by yokesd 61 A tare-bar E lies between the two bars d d. In the form shown inFigs. 1, 2, and 7 this bar is tubular, whereby it is especially adaptedto support, inclose, and cooperate with the particular form of bufiersprings employed. Suitable means are provided for preventing lateralmovement while permitting longitudinal movement of said bar relative tothe frame D. In the construction shown two pins e,which project from thesides of said bar, enter vertical slots cl in the proximate faces of thebars (1 d. On the lower end of the bar E is a threaded stem 6 whichenters-a socket d in the yoke 61 A nut 6 upon this stem lies inhorizontal slots d in the bars (1 d, wherefore by the turning of thisnut the bar E is moved end- 0 wise relative to the frame D. A spring dmay be compressed in the socket (Z below the stem c, the function ofsuch spring being to take up lost motion of the nut e in slots (1.

As stated, the bar E is a tube in the con- 5 struction shown in Figs. 1and 2, and both ends are wholly or partly closed sufficiently to formabutments for the springs. A vertical plunger-rod G passes centrallyinto the said tube through the upper end thereof. The rack-bar K isconnected to the upper end of this plunger-rod by suitable means, whichmay be and, as shown, are substantially like the means by whichheretofore a similar rackbar has been connected directly with thespring-framethat is to say, by a horizontal pivotthe rack-bar beingconstantly pressed by a spring 7.; toward the pinion b. This rackbarengages with the pinion Z2, which is rigidly connected with the shaft B.The rackbar K and pinion b constitute the best form of shaft-operatingmechanism. Inside the tube E and about midway between its ends is aninternal flange 6 On the rod G is an external flange g, which is of suchdiameter that it may pass the flange e Surrounding the rod G, onopposite sides of the flanges g and 6 are the two thimbles M M, whichfit upon the rod and in the tube, although they are freely movablerelative to both, wherefore said thimbles act to hold the rod Gcentrally in the tube E. The coilsprings N N surround the rod G in thetube and even when the scale is at rest are respectively compressedbetween the ends of the tube and the thimbles M M. The springs exertconstantly upon the thimbles force enough to normally hold them incontact with opposite sides of the flange 6 and to return them intocontact therewith when in the operation of the scale they have beenmoved out of contact. The opposite faces of the flange c act as stops tolimit the movement of said thimbles, and since the thimbles engage withthe flange 9 they (said springs) act to move said flange g to andnormally hold it in the same plane with the flange c and consequentlyact to return the rod G to a certain definite position relative to theframe D. It is evident that the plunger-rod G may move in eitherdirection from its normal position relative to the tube E, the springs NN yielding to permit such motion. This movement,when downward, isresisted by the spring N and is limited by the engagement of the lowerend of the rod G with the bottom of the tube E. \Vhen the movement ofsaid rod is upward, it is resisted by spring N and is limited by a loosesleeve P, which surrounds the rod G inside of the spring N and whichwhen said spring is sufficiently compressed engages with the top of thetube and with the thimble M. The described means for limiting themovements of the plunger-rod away from its normal position relative tothe tube E are provided for the purpose of preventing the springs frombeing too much compressed, whereby they may become set.

The operation of the described mechanism is the following: When a weightis thrown suddenly upon the scale-pan, the frame D and the tubular bar Eare jerked down. This motion of the frame and bar E must be transmitted,through the spring N, plunger-rod G, and rack-bar K, to the pinion Z)before the shaft 13 is moved. The strength of the spring, however, isnot great enough to immediately overcome the inertia of the parts named.The spring, therefore, yields or is compressed and permits the frame Dand tube E to move independently of the plun ger-rod an d the partsnamed connected therewith. The sprin subsequently expands to its normalcondition, whereby the rod G is'drawn down to its normal positionrelative to the frame D, as above described, and consequently is drawndown a distance proportionate to the weight upon the scale-pan, and thismovement of the rod effects, through the mechanism described, theproportionate rotation of the shaft 1 and indicator attached thereto.hen a weight is suddenly taken from the scale-pan and the frame D ismoved suddenly upward by the springs 11 II, the lower spring N yields,permitting the l)lll1]gl-1'0d G to temporarily re main stationary, andthen expands to return said rod to its normal position relative to saidframe B, wherefore the shaft B and indicator rigidly attached theretoare returned to their normal positions. Obviously the sprin act togradually check all movements of the rod G relative to the frame, orvice versa, and also to return said rod to its normal position relativeto the frame D.

It is necessary with the construction shown to prevent the plunger-rod Gfrom turning upon its axis in the tube E, and to effect this result alongitudinal groove 9 is formed in it, and a pin 6, which passes throughthe wall of the tube E, engages in this groove. As before stated, thetubular tare-bar E is adjustably connected with the frame D, and themeans described for moving it relative to said frame are provided forthe purpose of taking off tare, and it operates in the following manner:lVhen a vessel is placed upon the scale-pan, it draws the frame Ddownward, carrying with it necessarily the tube E and all of the partsassociated with said tube. By turning the nut e" the tube may now bemoved upward relative to the frame D until the dial or other indicatorattached to shaft B has been returned to its normal position. Thereafterthe mechanism will act in the described manner and will show the correctweight or value of the material placed in the vessel.

It will be understood that when the scale is used for ascertainingweights or values the bar E is rigidly connected with frame D and may beconsidered as a part of it.

In Figs. 5 and 6 I have shown a modified construction of the spring-buffer which serves to connect the frame D with the shaft'operatingmechanism. The two spring-arms N N which are secured to arms 6 on thetarebar E, act against opposite sides of a lug 1' on the slide R, (whichcorresponds in function to red G,) having a sliding connection with thetare-bar E, which is not tubular in this case. The spring N acts to movethe slide R down until said spring strikes the stop e on the tare-bar E,and the spring N acts to move said slide up until the spring strikes astep e" on said tare-bar. Both springs yield to permit independentmovement of the frame D IIO and slide R. The rack-bar K is connectedwith slide R in a suitable manner.

In Fig. 7 is still another modification of the invention. A tubular barE is to be attached to the frame D. The plunger-rod G enters the saidbar through its upper end. Only one spring N is employed. It liesbetween the two thimbles M 'M and is under constant tension sufficientto force said thimbles respectively against two internal shoulders 6 6On the rod G are two flanges 9 9 which are respectively above and belowsaid thimbles. This rod G is to be connected with the shaft-operatingmechanism substantially as shown on the other figures. WVhen the frame Dis violently-moved downward, the upper shoulder e pressing againstthimble M will compress the spring N and the subsequent expansion of thespring will press thimble M down against shoulder 9 When the frame D ismoved violently upward, it carries the lower thimble M upward, therebycompressing the spring N, which will expand again and move thimble M upagainst the shoulder 912. These movements of the thimbles when thespring is compressed are not necessarily accompanied by the movement ofthe rod G;

but as the spring expands these thimbles M of said thimbles.

The tare-bar, whatever be its shape, is rigidly connected with the frameD when the scale is being used for weighing, and therefore for thepurposes of the invention may be regarded as a part of said frame. Therod G or slide Rand the springs and associated parts constitute what Icall the double-acting spring-buffer, and the pinion b and rack-bar Kconstitute the shaft-rotating mechanism. Each of these three groups ofparts may be varied to any desired extent without departure from thegeneric invention.

Having described my invention, I claim- 1. In a spring-balance scale,the combination of a vertically-movable spring-frame, a rotatableindicator-operating shaft, shaft-r0- tatin g mechanism, avertically-movable member which forms part of said shaft-rotatingmechanism, which member has a sliding connection with the spring-frame,whereby they may move relatively to each other, and a double-actingbuffer device which opposes said relative movement of the frame andmember in both directions from their normal positions, substantially asspecified.

2. In a spring-balance scale, the combination of a vertically-movablespring-frame, a rotatable indicator-operating shaft, shaft-rotatingmechanism, a vertically-movable member which forms a part of saidshaft-rotating mechanism, which member has a sliding connection with thespring-frame, whereby they may'move relatively to each other, adoubleacting spring-buffer device which opposes the relative movementsof the frame and member in both directions from their normal positions,and stops which limit the positive action of said buffer device uponsaid shaft-operating member, whereby it always comes to rest in the sameposition relative to the springframe, substantially as specified.

3, In a spring-balance scale, the combination of a vertically-movablespring-frame, a rotatable indicator-operating shaft, a member which ismovable vertically relative to the frame and has a sliding connectiontherewith, mechanism for transmitting motion from said member to saidshaft, and a double-acting spring-buffer device which is under tensionin both directions when said member and frame are in their normalpositions, and acts to resist the relative movement of said parts inboth directions, substantially as specified.

4. In a spring-balance scale, the combination of a vertically-movablespring-frame, a rotatable indicator-operatin g shaft, a member which isslidable vertically upon the springframe, mechanism for transmittingmotion from said member to said shaft, a double-acting spring-bufferdevice which, when said member and frame are in their normal positions,is under tension in both directions, and acts to resist the relativemovement of said parts in both directions, and stops which limit thepositive action of said spring-bufler device in both directions, wherebysaid parts are brought to rest in their normal relative positions,substantially as specified.

5. In a spring-balance scale, the combination of a vertically-movableframe, a rotatable indicator-operatin g shaft, a member which isslidable vertically upon said spring-frame, mechanism for transmittingmotion from said member to said shaft, and two buffer-springs interposedbetween the frame and verticallymovable member and acting upon saidmember in opposite directions, and stops carriedby the frame with whichsaid springs respectively engage under tension when they have returnedto their normal positions, substantially as specified.

6. In a spring-balance scale, the combination of the spring-supportedframe, a tube secured thereto, having near its middle an internalflange, a plunger-rod entering one end of said tube and passing saidflange, an external flange on said rod, two springs under tensionsurrounding said rod in the tube, and adapted respectively to thrustendwise against the ends of said tube and the flange in the tube and theflange on the plunger-rod, substantially as specified.

7. In a spring-balance scale, the combination of the spring-supportedframe, a vertical tube secured thereto having closed ends and aninternal flange between the ends, a plunger-rod passing into the tubethrough the upper end thereof and having an external flange,freely-movable thimbles which fit said tube and embrace said rod onopposite sides of said flanges, and two springs respectively compressedbetween the end of the tube and said thimbles, a rotating indicator, andmechanism for transmitting motion from the plunger-rod to the indicator,substantially as specified.

8. In a spring-balance scale, the combination of the spring-supportedframe, a vertical tube secured thereto having closed ends and aninternal flange between the ends, a plunger-rod passing into the tubethrough the upper end thereof and having an external flange,freely-movable thimbles which fit said tube and embrace said rod onopposite sides of said flanges, and two springs respectively compressedbetween the ends of the tube and said thimbles, a rotating indicator,and mechanism for transmitting motion from the plunger-rod to theindicator, and stops to limit the relative movement in both directionsof the plunger-rod and tube, substantially as specified.

9. In a spring-balance computing-scale, the combination of thespring-supported frame, a vertical tube supported thereon and having aninternal flange, and means for changing the relative positions of saidtube and frame,

a plunger-rod passing into said tube through its upper end and having aninternal flange, two springs in the said tube arranged to re spectivelythrust against the ends of the tube and on opposite sides of the twoflanges named, with a movable indicator and mechanism transmittingmotion from the plungerrod to the indicator, substantially as specified.

10. In a spring-balance com puting-scale,the combination of thescale-ease, a rotatable shaft, an indicator rigidly attached thereto,and shaft-operati n g mechanism, with a spriu supported frame, atare-bar adjustably secured thereto, a double-acting spring-buffer underconstant tension supported by said tare-bar and connecting the same withthe shaft-operatin g mechanism, and stops carried by said tare-bar forlimiting the action of said spring-buffer upon the shaft-operatingmechanism, substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

J OIIN HENRY S\VIITART. \Vitnesses:

E. L. TI-IURSTON, ALBERT II. BATES.

